Supergirl season 1 episode 18

Air Date: 2016-03-28

Duration: 42 min

Genre: Action   Adventure   Drama   Fantasy   Sci-Fi

Worlds Finest

Kara gains a new ally when the lightning-fast superhero The Flash suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire in exchange for her help in finding a way to return him home.